I don't have Windows Media Player 11 installed, probably never will install it.
The WindowsServer2003.WindowsXP-WindowsMedia-KB2834904-v2-x64-ENU.exe update will not install without WMP11 installed.
The KB2834904-v2.log file says:
0.032: C:\WINDOWS\SysWow64\wmvdecod.dll is Not Present
0.032: Fist Condition in Test.Exist.WM11.Section.wmvdecod Failed
0.032: Condition Check for Line 1 of PreRequisite returned FALSE
0.047: KB2834904-v2 Setup encountered an error: Windows Media Player must be on your machine before this software update can be installed. Please install Windows Media Player and launch this software update again.

Is there a method for the .APM to first look for the presence of the wmvdecod.dll file, or something in the registry, before presenting the update in black on the updates list?
I know that I can right-click and select "never show this item" but, I may change my mind someday and decide to install WMP11. Then I might not remember that I had permanently hidden the update.

I found an example that showed me the answer.
I added:
[SystemComponents]
InternetExplorer=ANY
WindowsMediaPlayer=ANY
DotNetFramework=ANY
WindowsInstaller=ANY
DirectX=ANY
MSNMessenger=ANY
ComponentFile=windows:\SysWow64\wmvdecod.dll

to the "KB2834904-v2-x64-ENU.apm" file so now the "Security Update for Windows Media Format Runtime 11 for Windows XP SP2 and Windows Server 2003 SP2 x64 Edition (KB2834904-v2)" update is no longer presented in the listing since I do not have WMP11 installed.